comfortmaker flame sensor

I have A comfortmaker furnace. The draft motor turns on,glow plug lights,burners fire up. After about 7 seconds burners go out and the blower motor never turns on. I thought the flame sensor was bad,cleaned up with emery an installed,same problem. My question is can you test the flame sensor with an ohm meter. right now I have 0.4 ohms put A propane torch flame close to the end and my reading stayed the same.Is this flame sensor good or bad.